The present invention is directed to a device and method for removing a carton from a mandrel in a packaging machine. More particularly, the present invention is directed to a vacuum-assisted device and method for removing a partially erected carton from a mandrel in a form, fill and seal packaging machine, that minimizes the opportunity for inadvertent contamination of the machine.
Form, fill and seal packaging machine are well known in the art. These machines are widely used in the food packaging industry for forming a package, filling the package with a liquid or solid food (or a mixture of liquid and solid foods), and sealing the package after filling.
In such machines, sterilization, generally, must be kept at a maximum. That is, all of the carton contacting surfaces must be maintained at a high level of cleanliness in order to reduce the opportunity for product contamination. A number of processes and philosophies are carried out in such machines in order to maintain the requisite high levels of cleanliness. One such philosophy is to minimize contact with food-contacting surfaces. That is, minimal if any contact should be made with any machine surfaces that come into contact with a food-contacting surface (such as the interior of a package, e.g., carton).
One primary example of this is in connection with carton mandrels. The mandrel is that part of the machine on which the carton is carried as the bottom panels are folded and sealed, to form the carton bottom. In a typical operation, a carton is taken from a flat, folded form and opened to an open ended tubular form. The tubular form is then inserted onto or over the mandrel. The mandrel has a rectangular overall shape and a cap that is a substantially flat, solid surface. The cap corresponds to the carton bottom location. The bottom panels are then heated, folded and xe2x80x9cpressedxe2x80x9d to form the sealed bottom wall. As such, the mandrel, and in particular the mandrel cap is in contact with the carton food-contacting surfaces.
Typically, the mandrel is mounted to a rotating turret. In such an arrangement, the turret rotates to the various positions for inserting a tubular blank onto the mandrel, heating and folding the bottom flaps, and sealing the flaps to form the sealed bottom. Subsequent to forming the sealed bottom wall, the partially erected carton (that is, the carton with the bottom wall formed and the top open for filling), is removed from the turret. Some known machines also include a pre-folding station, prior to heating, to pre-fold the bottom flaps.
In a typical arrangement, the carton is positioned on a conveying system for moving the carton through various stations for sterilizing, filling and top sealing. Generally, the sterilizing, filling and top sealing stations lie along a linear path and the carton is removed from the mandrel and positioned on a linear conveyor, such as a chain or sleeve and chain conveyor system. One exemplary conveyor system is that disclosed in Massey, U.S. Pat. No. 5,826,406, commonly assigned with the present application and incorporated herein by reference.
To remove the carton from the mandrel for transfer onto the conveyor, known systems use a stationary suction cup vacuum arrangement that is positioned on a moving arm. That is, the arm moves up to contact the bottom of the carton and pulls the carton from mandrel to position the carton on the conveyor.
The suction cup itself is, however, stationary relative to the moving arm. In such an arrangement, the suction cup, when the arm is in the raised position is located only a small distance from the mandrel cap when the mandrel is at the bottom station (the station at which the cartons are pulled). Generally, the gap between the mandrel cap and the suction cup is equal to the thickness of the folded and sealed bottom wall of the carton. That is, the gap is quite small. This is particularly true when non-flat carton bottom profiles are used. This assures that the carton will be grasped by the suction cup and removed from the mandrel.
While these systems function well to xe2x80x9cpullxe2x80x9d the carton from the mandrel, one drawback to this arrangement is that the suction cups, because they are formed from a soft material tend to deform over time. As such, the suction cup can be so deformed as to contact the mandrel cap when there is no carton on the mandrel. This is highly undesirable in that the mandrel cap can become contaminated by contact with the suction cup.
Accordingly, there exists a need for an improved suction cup-type, vacuum assisted device and method for pulling cartons from a mandrel on a form, fill and seal packaging machine. Desirably, such a device is readily usable on existing packaging machine. Most desirably such a device and method prevent inadvertent contact of the suction cup when a carton is not present on the mandrel, during machine operation.
A form, fill and seal packaging machine includes a carton pulling assembly for pulling a partially formed carton from a mandrel on the machine. The cartons are partially formed (that is, the bottom wall is formed) while carried on the mandrel. A plurality of such mandrels are carried on a rotating turret.
The carton pulling assembly includes a carton puller element movable in a reciprocating manner toward and away from the mandrel. A vacuum head assembly is mounted to the carton puller element for reciprocating movement therewith. The vacuum head assembly includes a cylinder and a finger configured for reciprocating movement within the cylinder.
A suction element is mounted to the reciprocating finger. The finger has a vacuum channel for communicating vacuum from the cylinder to the suction element. The reciprocating finger is movable between an extended position in which the suction element contacts and engages the carton sealed bottom wall and a retracted position in which the reciprocating finger pulls the carton from the mandrel. The reciprocating finger is movable toward the extended position by application of vacuum to the vacuum head assembly while communicating vacuum to the suction element.
In a present embodiment, the cylinder defines an upper region and a lower region separated from one another by a base portion of the reciprocating finger. The base portion extends outwardly to contact an inner wall of the cylinder to form a seal. The cylinder includes one or more vacuum channels extending upwardly, within the wall. The channels terminate at a port at the cylinder upper region for communicating vacuum to the cylinder upper region, to move (e.g., xe2x80x9cpullxe2x80x9d) the finger to the extended position for contacting and engaging the carton bottom wall.
In a preferred embodiment, a base plate is mounted to the base of the cylinder. The base plate has a transverse channel formed therein that is configured to distribute the vacuum to the cylinder vacuum channels. A vent extends between the finger vacuum channel and the cylinder upper region.
The suction element is seated and supported in a holder and a fastener extends centrally through the suction element to secure the suction element to the finger. The fastener is formed having a centrally disposed longitudinal bore for communicating vacuum from the finger vacuum channel to the suction element.
The vacuum head assembly is configured such that the finger, following engagement of the suction element with the carton, moves to the retracted position by application of vacuum to the cylinder lower region, through the vent.
A method for pulling a partially formed carton from the mandrel includes providing a carton puller element movable in a reciprocating manner toward and away from the mandrel. The carton puller element has a vacuum head assembly mounted thereto that includes a reciprocating finger having a suction element at an end thereof. A vacuum is communicated to the vacuum head assembly and to the suction element.
The finger is extended from the vacuum head assembly toward and into engagement with the carton bottom wall. The finger is retracted (i.e., moved away) from the mandrel and pulls the carton from the mandrel. The carton puller element is moved away from the mandrel and the carton is positioned on a conveyor of the machine. The carton is then released from the suction element.
In a present embodiment, the vacuum is selectively communicated to the vacuum head assembly, preferably when a carton is present on the mandrel.
These and other features and advantages of the present invention will be apparent from the following detailed description, in conjunction with the appended claims.